Miniaturized electrical components are widely used in a variety of consumer and industrial items, such as TV sets radios, cars, kitchen appliances, computers, etc. Advantages both in performance and price of miniature structures have made them common in the everyday life of consumers. Due to the popularity and need for miniature structures, such as computer chips, optical, chemical, biological, environmental, physical and electromagnetic detectors/sensors, and a variety of different types of passive electronic components, different manufacturing processes have been developed for fabrication of those structures.
These methodologies may include Direct Write processes, such as Laser Forward Transfer, or Laser Induced Forward Transfer techniques which require a depositable material to be transferred toward a substrate and deposited thereon to manufacture a single structure or a plurality of structures on the same substrate.
In the fabrication of miniature structures, subtractive processes using irradiation of the substrate surface-to ablate, evaporate, or otherwise remove material from the workpiece may be employed simultaneously. Laser surface cleaning is a well-known technique for removing surface contaminations such as particulate matter, thin layers of oil, or other organic/inorganic contaminants. Laser surface cleaning is carried out prior to the deposition of a depositable material on the surface of the substrate to promote adherence of the depositable material to the substrate surface and to enhance electrical contact.
Although being well developed and known to those skilled in the art, conventional irradiation surface cleaning has several drawbacks. Particularly; during the irradiation surface cleaning, substantially the entire surface of a substrate may be affected by irradiation including areas containing fragile or sensitive components as well as areas that are intolerant of laser, ion, or electron radiation. Such a wide area impingement may cause damage to the components located on the substrate surface.
Additionally, radiation of the entire substrate is surface consumes more laser energy than needed for the cleaning process, thus reducing the efficiency of the available laser energy.
Another drawback of conventional surface cleaning is encountered when a plurality of different materials exist on the substrate surface requiring different fluences of the laser beam to be cleaned or removed. Usually, these materials are spread over the substrate surface at different locations. Conventional cleaning (in which the entire substrate surface may be irradiated by the laser beam of the same intensity) cannot selectively clean separate areas containing different materials without complicating the process with additional steps such as the use of masks, photoresists, and other blocking mechanisms.
Still another drawback of conventional cleaning processes is related to the necessity of transferring the cleaned substrate from the “cleaning area” to a “deposition area”. During substrate transfer from one area to another, physical damage to the workpiece may occur. Additionally, the workpiece may be contaminated and the freshly exposed areas on the surface may be reoxidized, thus substantially reducing yield of high quality devices.
Accordingly, despite certain utility of the conventional manufacturing equipment and techniques for fabrication of miniature structures, particularly surface cleaning, a long-felt need exists for equipment and techniques in which surface cleaning and deposition may be carried out with the same fabrication tool which provides for selective surface cleaning of those areas where it is required or is effective. A need also has existed for insuring efficient utilization of available laser, ion, or electron energy, where the unwanted irradiation of surfaces containing fragile components or areas intolerant of radiation may be avoided as well as where the cleaning of the surfaces containing a plurality of different materials may be carried out in a simple and effective manner.